Abstract: A multi-stage extendable tower for controlled elevated support and positioning of workmen and equipment having a plurality of telescoping frame sections that may be raised from a collapsed nested position to a partially or fully extended position. Functionally positioned and interconnected between each adjacent frame section is at least one heavy-duty coiled spring whose potential energy stored in torsion provides sufficient lifting force to overcome the weight of the above frame members, workmen and equipment. Both manual and motorized means are disclosed and claimed for effecting compression and renesting of the frame members.

Abstract: A guyline tensioner for communication towers is provided wherein the towers are of the type having a plurality of nested sections which are raised and lowered by a telescoping action. The device of the present invention provides a guying means so that as the tower is raised or lowered, a single operator can maintain equal tension on all of the guys at the same time.

Abstract: A multisection hollow telescopic boom comprises a base section, an intermediate section and a fly section. A first elongated rotatable screw located within the boom has its base end rotatably mounted on the base end of the base section and engages a first nut which is rigidly mounted on the base end of the intermediate section. A second elongated rotatable screw located within the boom has its base end rotatably mounted on and connected to the base end of the intermediate section and engages a second nut which is rigidly mounted on the base end of the fly section. A screw drive rotates the screws to effect axial telescopic movement of the boom sections. In one embodiment the screw drive comprises a single motor for driving the first screw, a first sprocket rotatably driven by the first screw, a second sprocket for rotatably driving the second screw, and a drive chain connected between the sprockets.

Abstract: An aerial lift is described which has a pivotable boom with a load end and a pivot end. The boom is constructed such that, as the pivot end of the boom pivots upwardly, the load end is raised substantially vertically. In one embodiment, the boom is mounted on a telescoping scaffold to provide the boom with a greater reaching range. In another embodiment, the boom itself is provided with telescoping members to extend its vertical reach.

Abstract: An extendable column consisting of a plurality of axially elongated rigid structural sections nested within one another. Each section includes a plurality of screws running the length thereof and rotatably attached therein. The next inner section includes threaded lugs oriented to threadingly engage the screws thus resulting in extension or retraction of the column upon rotation of the screws. The screws of each section are selectively rotated by a motor and an engagement mechanism.

Abstract: Method and apparatus for transporting a sectional tower to a selected location and for erecting the tower at the selected location is disclosed. The apparatus includes a mobile trailer bed on which the erection apparatus and the tower sections are transported. A frame is carried on the trailer bed which has racks on which a number of tower sections are stowed. A folding guide member is pivotally attached to the trailer frame and is rotatable to a stowed position during transportation and is rotatable to an upright position for guiding the tower during erection. A hoist is carried on the folding guide member for raising the tower sections through the guide member. A plurality of sheaves are attached to the support frame and upon a number of anchors symmetrically disposed at radially spaced locations relative to the support frame. Guy wires are attached to the uppermost tower section and are reeved with the sheaves associated with each anchor and are coupled to a winch.

Abstract: An assembly for positioning a crane mounted on a support and intended to overhang the platform of a platform structure having a base which rests on the bed of a body of water. The crane is located on the vertical axis of a column offset with respect to a central shaft which carries the platform. The assembly comprises a mobile shaft element contained in the upper part of the offset column and having a base with jacks or a block and tackle permitting its emergence as far as the upper level of the offset column. The lower face of the crane support carries a downwardly extending shaft element which has the same diameter as the mobile shaft element. The two shaft elements are substantially coaxial when the platform is carried on the central shaft so that they may be joined together and raised as a unit.

Abstract: An aerial lift is described which has a pivotable boom with a load end and a pivot end. The boom is constructed such that, as the pivot end of the boom pivots upwardly, the load end is raised substantially vertically. In one embodiment, the boom is mounted on a telescoping scaffold to provide the boom with a greater reaching range. In another embodiment, the boom itself is provided with telescoping members to extend its vertical reach.

Abstract: A mobile crane for use on an offshore oil well platform, comprising parallel base beams adapted to span the capping beams of the platform, and a pedestal and a rotating upper works movably mounted on the base beams. A method is described for erecting a workover rig on the offshore platform by means of the crane, and for expeditiously erecting workover rigs on a plurality of platforms in succession.

Abstract: A flagpole assembly for automatically displaying and furling a flag. The assembly is formed of a first hollow vertical slotted pole mounted concentrically inside a second slotted hollow pole with both poles mounted to a base. A cable, mounted on pulleys extends inside the first pole with the flag fixed to the cable, and extending through the slot of the first pole, and when displayed, extending through the slot of the second pole. The second pole is rotatably mounted to the base. A motor unit serves to wind the cable pulleys and rotate the second pole for furling or unfurling the flag, with associated sensors and limit switches serving to furl the flag during periods of darkness and periods of rain.

Abstract: In "flying forms" having a plurality of trusses -- usually two -- with a plurality of beams placed across the trusses and a deck placed on the beams, an extension leg for the truss is provided so that the working height of the truss may be nearly twice its flying height. The extension leg replaces a truss upright, and mounts using the same bolting arrangement therefor. The leg comprises inner and outer legs, where the outer leg is secured to the top and bottom chords of the truss, and the inner leg is telescopically engaged within the outer leg. The shape of the inner leg is such as to accommodate the bolts which secure the outer leg to the truss chords. Holes are formed in the inner and outer legs with predetermined spacings, and pairs of pins are used to lock the inner leg in any desired position with respect to the outer leg at substantially the desired height.

Abstract: An aerial lift including a pivotable boom with a pivot end that moves horizontally as the load end of the boom is raised and lowered, allowing the load end to move along a substantially vertical line. The boom is mounted on a vertically adjustable, substantially horizontal mounting table which cooperates with the boom to provide a lift with a greater reaching range.

Abstract: The telescoping elements of an extensible rod may be coupled sequentially to a coaxial, partly threaded spindle by respective internally threaded coupling members, each element being drivingly engaged with the spindle by a previously engaged, abuttingly coupled element. A yieldably resilient mounting for the coupling member or for one of two cooperating abutment members permits smooth engagement of the spindle threads with the coupling members.

Abstract: Telescopic columns for making foundations including in reciprocal coordination and cooperation a motor group comprising at least two guide pulleys having a proportion to each other of one to two; inner and outer movable columns; axially immovable canoe guide means surrounding said columns; a chain secured to the two ends of the outer movable column and driven by the smaller of said pulleys; a chain secured to the lower part of the inner movable column and to the upper part of the axially immovable guide canoe means and driven by the larger pulley; a cable connecting the upper part of the inner movable column to the lower part of the axially immovable guide canoe means and a transmission sheave solidly fixed to the lower part of the outer movable column through which passes said cable.

Abstract: A system and method are disclosed whereby a crane boom assembly of relatively long length and large load carrying capacity may be automatically stowed and carried on the superstructure of a crane assembly. With the boom assembly in the stowed position, the boom and superstructure combination may be carried on a single truck and trailer combination for highway transport. Power driven means are provided for unstowing and stowing the boom assembly with respect to the superstructure. To unstow the boom assembly, first power driven means are provided to translate the boom forwardly with respect to the superstructure. Foot pins located at the rear of the boom assembly are mountable in the main pivot means on the superstructure of the crane when the boom assembly is fully extended forwardly of the superstructure to an intermediate unstowed position.

Abstract: A telescopic boom of a crane comprising a base element adapted for support on a turret of the crane, and a plurality of telescopic elements slidably engaged within one another and within the base element. The elements have a polygonal cross-section, each element having a lower or inner compression leg of inverted V-shape which opens downwardly and falls the load. First guide shoes are mounted on each telescopic element on the upper or outer leg thereof, bearing against the surrounding element, and second guide shoes are mounted on each branch of the inverted V-shaped inner leg also bearing against the surrounding element.

Abstract: An improved boom includes a slider assembly for use in supporting telescoping sections of the boom for movement relative to each other. An articulated slider assembly embodying the invention includes a rocker member which is pivotally mounted on one section of the boom. A pair of slider block assemblies are pivotally mounted on the rocker member and slidably engage a supported section of the boom at spaced apart locations. Deflection of the supported boom section is compensated for by pivotal movement of the slider block assemblies relative to each other. A spring type slider assembly forms another embodiment of the invention and has a flexural rigidity such that the deflection of the spring type slider assembly matches the deflection of a supported section of the boom under the influence of an operating load to provide for the transmittal of a uniform bearing load between the supported boom section and slider assembly.